Metal spray gun of the wire feed type



Aug. 14, 1945. A. P. SHEPARD ErAL 2,382,111

METAL SPRAY GUN OF THE WIRE FEED TYPE I Filed July 15, 1943 7 Sheets-Sheet 1 INVENTORJ A TTORNE Y Aug. 14, 1945.

A. P. SHEPARD EI'AL METAL SPRAY GUN OF THE WIRE FEED TYPE Filed July 15, 1943 7 sheets-shee 2 mmm mwm QR Qn i Rum QNm mom R im mam 8m Q E mom Z'YVENTORS: flri/zw R Shepard Herbert S. I

t- 1945- A. P. SHEPARD EIAL I METAL SPRAY GUN OF THE WIRE FEED TYPE Filed July 15, 1943 7 Sheets-Sheet 3 J02 I -T 6 z w J 104 10s 107 Aug. 14, 1945. A.P. SHEPARD EI'AL 2,332,111

METAL SPRAY GUN OF THE WIRE FEED TYPE Filed July 15, 1943 7 Sheets-Sheet 4 A TTORNEY I A. P. SHEPARD HAL 2,11

, METAL SPRAY GUN OF THE WIRE FEED TYPE Filed July 15, 1943 '7 Sheets-Sheet 5 rt/lur .Sbe rd gel-kl"? 5.1452200 ATTORNEY 7 Sheets-Sheet 6 3v av ATTORNEY 14, 1945- A. P. SHEPARD ETAL METAL SPRAY GUN OF THE WIRE FEED TYPE Filed July 15, 1943 A. P. HEPARD ETAL METAL SPRAY GUN OF THE WIRE FEED TYPE Filed July 15, 1943 7 Sheets-Sheet 7 INVENTORS:

A TTORNEY Patented Aug. 14, 1945 METAL SPRAY GUN OF THE WIRE FEED Arthur P. Shepard, Flushing, and Herbert S.

. Ingham, Queens Village, N. Y., assignors to Metallizing Engineering Co. Inc., Long Island City, N. Y., a corporation of New Jersey Original application December 1, 1941, Serial No. 421,196. Divided and this application July 15, 1943, Serial No. 494,810

8 Claims. (01 25 s59) This invention relates to new and useful improvements in metal spray guns of the wire feed type.

Metal spray guns of the wire feed type are devices in which a metal rod or wire is continuously fed into a melting zone, from which zone the metal is propelled in finely subdivided form by suitable means such as a blast of air or other gas. The rod or wire is fed into the melting zone by suitable rod or wire feeding means, such as knurled burs pressing against opposite sides of the wire. I These wire or rod feeding means. are

driven, preferably operating through reduction gears, by a compressed gas motor, i. e., a motor, the rotor of which is rotated by the force of compressed gas. The loadon the motor varies from time t time due to the changes in the position of the operator, kinks in the wire, etc. Since it is essential for successful spraying operations that the ratio of feed of the wire be uniformly maintained, it is likewise essential that the motor have a comparatively stable speed of I operation, i. e., that its speed of operation be affected as little as possible by variations in the load. One common form of compressed gas motor is a compressed gas turbine and our invention shall be more slowly than smaller diameter wires of the same material.

It is the usual practice to attempt the approximation of the proper conditions for the particular metal to besprayed by providing for replace-;

able gearing designed to permit the gun to be operated at the required rate of wire feed and to permit the turbine to operate within a range of stable operation. Changing the gearing, "however, involves loss of time and the possibility that metal particles will be picked up by the gears in handling and interfere with the operation of the gun. When attempting to eliminate gear changes by reducing the turbine speed through a throttling of the blast gas supply, the turbine becomes unstable and a uniform wire feed is no longer maintained as the then available power is insuflicient to compensate for load increases.

I This operating instability of the ordinary gasblast operated turbine particularly at lower speeds, has been'a serious disadvantage in metal I, spray gun constructions hitherto used. Although it may be possible in a given case to maintain ,a' satisfactory wire feed, the ordinary gas turbine is verysusceptible to variations in the operating load. The ordinary gas turbine has sufficient powerfor feeding the wire under normal condi-q tion's as long as a suflicient quantity of gas, is

10 pressure. The power requirements of the tursupplied to the turbine rotor at a sufficiently high b ine, however, necessitate the feedin thereto of suflicient impelling gas to causejthe turbine. to operate at a very high speed. At whatever speed, however, the turbine operates with a given inflow and pressure of gas, all the power is used up and no excess power is available to take care of variations in the operating load.

' The governing mechanism in accordance with the invention is variably adjustable to procure different perating speeds and yet is capable at anygiven speed to make excess power practically instantaneously available when required by sudden overload.

Our governing mechanism broadly comprises means positioned and adapted to control the compressed gas supply to a compressed gas motor of a metal spray gun of a wire feed type and com-: posed of at least one first and one second elemen't, said first element "being positionedand adapted to be operatively acted upon by suitable centrifugal speed responsive means tucooperate, by mechanical movement'with said secondrele ment to thereby restrict the compressed gas sup-' ply'to'therotor of said motor, and'means for variably adjusting the relative position between said second elementand the initial position f said first element within a range of mechanical movement of said first element defined by the ,operating positions of said speed responsive means between minimum and, maximum operat-v ing speeds of said rotor.

Ingeneral, the selection of anyparticulari speed responsive device'or the particular-bon w structionthereof depends, inter 81113;, upon considerations of-design, practicability, desired-adcuracy and sensitivity intended capacity of the metal spray gun etc., but foremost upon the speed range within which such gun is to operate. The

' latter'. factor is of importance as manymetal spray guns of the herein mentioned type normally operate within a speed range wherethe maximum operating speed is in excess of 200% of the minimumoperating speed. I

. construction makes. it possible for thefirst. time Within the preferred embodiment of our invention, therefore, cognizance istaken of the fact ing for variations in speed at which it must be governed over a wide range of operating speeds.

operation of one particular gun of this type may be from 6,000 revolutions per minute (100 R. P. S.) to almost 40,000 revolutions per minute i (666 R. P. 8.). This is a speedinerease from, lowest to highest usable speed l-Ioflover 500%. ;With any governor utilizing-.centrifugaL force; 1-

thi condition presents a particularly aoute=:prob'-- lem because of the fact that. centrifugal force 1 varies as the square of the rotating speed. This fmeans that if the ordinary centrifugal governor .were added to the. rotor of a metallizing gun,

which operates through a 6 times speed; range, the force operating von the governor. weights would vary 36 times from lowest to highest speed and a mechanical. movement actuating the governor mechanism would be subject toequally" great variationsso that it is in such case practically impossible to obtain. the necessary sensitivity at each and every speed throughout the range.

which. controls the speed, is .150 between lowest and highest operating speed of the gun and if,

tenths of the speed range could. only actuate the mechanism through a total movement of .075"

which isthe remainingdi'stanced .This would be an insufficient movement oi the mechanism. for

so wide a speedrange, and the governor would not be sensitive, nor perform satisfactorily- The governor in accordance with our preferred.

to utilize a governor of the centrifugal ty e togovern the rotor of a metal spray gun oi the wire feed type through a. wide speed rangewhereby :the governing action,,i. e, the mechanical movement of the actuationmechanism is substantially lapproximately proportional to the change in speed of the rotor throughout the speed range covered by: the governor.

The principle'underlying the preferred construction of the centrifugal speed. responsive When the governor element rotates at an angular velocity about itsaxis Y, centrifugal force acts on the mass M in a direction perpendicular to the axis Y. This force is indicated by the vector arrow F. The force'F can be considered, to be resolved into a component force indicated by vector arrow C, perpendicular to the arm Z, and a component force indicated by the vector arrow S, in the direction of' the arm Z.

The componentfo-rce C tends to deflect the arm and, assuming the latter to move outwardly against a spring resistance; indicatedby the vector arrow P. is balanced by'the spring resistance In a specific case, for instance. if the total movement of the governing mechanism,-

P at any given operating position of Z.

This

' spring resistance P is defined by K in which K curately with a -sensitive speed governor allow- T i's'the time: required for one revolution and Qm-ayfbeexpressed iin R. P. S.

mechanism in accordance with the inventionwill is the unit spring force in dynes for unit angular deflection onl'fpe for eachde'greezoi deflection of Z, through'agiven rangeof deflectionor corresponding value of .For instance, the speed range for the active as C is balanced by the spring resistance of K=M21r lsin' '2 ('11) "R.P.S'.Q- U

K 2,2 2 w t t 2 15 may be expressed in radians or degrees is appropriately chosen). v Assuming as a representative example'an'cioperating range of from 6000 to-40.000 R. P; M; (100% to 666 R. P. S.) and a total maximum. deflection-- of 88 at a maximum-speed of1666 R; P. S.,. the value of-K for equilibrium-at that deflection may be foundv by inserting thevariouswalues in Equation l2'resolved for K. I v

Having established the unit value'K for each de 'gree of deflection through a range from-0 to 8'3" with a maximum of 666 R". P. S; at= 88, Equation 12' may be resolved for the determination of R. PJS'. for. different deflectionsof l or values of qfi.

v I R-P-s. T The R. P: S." values obtained for difierent values ofparei listed inzthe following Tabl I. i Table} I [Deflection range 088] 1o '20. 30 40,150 60. 70-30. (es.

When plotting the curve defined by Equation- 12 in accordance with the values given in TabIe'I the curve hasa slope as demonstrated by curve Iin Fig. 1. When using instead of an arm controlled by a spring force acting throughout the'entire range of to 88, an arm controlled by a spring force acting through a range beginning with a predetermined initial position at the angle '7 of the arm 1 with respect to the axis. of rotation Y, a different value for K controls. This value is defined by Equation 13 exceptthat the .value for 4 =(88-''y).

a 2 w H 271' RPS. sin 2(889- (88 (15) The values of K obtained for diflerent values of 'y are listed in the following Table A.

The R. P. S. values in accordance with -Equation 14 for predetermined angles of 'y are determined by R-P-S.

The R. P. S. values for different values of and for each series with constant predetermined values for 'y and corresponding constant values for K are listed inthe following Tables II, III, IV,

V, and VI.

Table II1 [Deflection range'yto 88] v 40 41 50 60 80-! 105-, gas

R.P.S 0 28.8 01.3 137.7 105.7 300:3 401.0: oco

Table 111 v f [Deflection range-yto 88] 50 51 00. 70. so s5 88 ans 0 32.50109.41 179.0 309.8 401.2 we

Table IV [Deflection range'yto 88] I 60 01 u 70 R.P.S 0 40.7'1479 TableV i [Deflection range'yto 88f] :70 70 71 i i/5 as R.P,S 0 59.01479 2521104340 Q 4 1 i The curves plotted for each series of values for dand R. P. S. given inthe foregoing .tables, are illustrated in Fig. 15 as II, III, IV, V and VI corresponding respectively to thetables of the same designation..,,. f

Analyzing these curves, it will be seen that in each curve there is a section or, sections the slope of which roughly approximates a constant, i. e.,, for approximately. equal increments in vR. P- S.

there are] approximatelyjuniformincrements in angular deflection H-of the arm I. This permits 7' the speed governing mechanism to be variably ad iustedto any desired R. P. .S. throughout the R. P. S.- 'range defined by the particular constant slope curve section an'd to thereby attain an. approximately accurate, uniform and sensitive. speed governing operation. v p g It, will be seenhowever thatthe diiferent con stant'slope curve sections ofthe various curves differ in the R. P.,S.. range covered by such curve section. Thus, for instance, the section of curve Ibetween; 10 and 70 angulardeflection, though roughly approximating a, constant in its slope, has a very steep pitch with respect to the abscissa and jcoversfor a total of .deflection an R. P. S. range of only from 115 to 220 R.' P.-S. thatis a total R. P. S. range of only 105 R. P. S. As to the curvesectibns of curve I between and 85 angular deflection and and 88 angular deflection, the pitch with'resp'ect to theabscissa of these sections is ,notas steep. As to the section between 70?, and angular deflection of curve I,

deflection the R. P. S- range is from 330 to 666 or agto'talof only .333 R.,P. S. for 8 deflectionfi It is ,thusfl seen from the analysis oicurve I thatthere isno single constantslope 'sectionin this curve defining anywhere an R. P. S. range covering in, excess 'of 200% speedyariations. Though a governor element operatin within the range defined by curve I may beused within the limitations inherent therein, such governorele merit is'ordnarily not satisfactory in the case of a metalspray gun of the gas blast typenormah ly. operating-within a spe'edrange where the maximum operating range is in excess of 200% of the minimum operating range. 1 e r I The dotted outlines of the various curves rep: resent .the plotted slopes below minimum'pperatirig R. P. S. i. e., 1 00 R. P. S. ofthedevioe in accordance with this illustration.

. Analyzing the curves based on a predetermined initial, angular position of the, arm 1 (curves II, III, IV, V and VI)" it will be seen that curves II and In do not possessfanyv section above minia mumoperating R. P. S. of for which the mum .op era'ti'ngR. P. s. 013.666 which is equivalent to an R. P. S. rangecovering in excess of 500% speed variation, In, these'cases the approximation of a constant increases with themcrease in the predetermined initial angular position of the arm. with respect to the axis of row,

I I tation and, although for practical operationa predetermined angle of 70, as exemplified'by curve IV, will give satisfactory results, higher angles as illustrated by curves V and VI are preferred. Although the constancy of slope' improves with higher initial angles, it has been; found that the. governing element with 'too high a predetermined initial angle may lose sensitivity.

For best results an arm having its spring set for a predetermined initial angular: positi'onbetween operating range of 100R." Pf. S;and a maximum operating range of 666 RQP. S with an assumed maximum deflection. of88:" havebeen selected it is understood. that these values are merely used by way of'exemplification offtheprinciples under lying the-preferredembodiment of our invention. The results are not substantially different and the same type of curves result if other values er ranges are substituted. for those hereinabove used. I

The variable speed governing mechanism, in

accordance with the preferred construction of the invention, for a metal spray gun of the wire feed type, having a. compressed gas motor, comprises atleast one arm, rotatable with the rotor of such motor and centrifugally deflectable for. angular deflection with respect to its axis. of rotation; against spring resistance, and a predetermined initial position and preferablyfrom a predeter minedinitial position of at least 60 with respectj to such axis; speed control means, composed of at-leastone first and one. second element, the

stantia'llyr stable operating conditions; over a. much wider range: of.-wire feed speeds than otherwise possible. .The invention will; beamoreffully understood and further objects thereofiwill appear-from" the following descriptioni-read; conjunction: with" thedrawing's in which:

' Fig'zr-l is aside view: of a metal spray' gun illus' trating' one? embodiment of a construction in accordance-withthe inventiony- Figifizxis a" vertical: section through. the con.

struction shownin Fig. 1 on the planexind-icated housing construction shown in Fig. 6; V v

Fig. 7 is a side view of the rotor element of the spraygun 8 is .a' view of part of the construction shown in Fig. 7 at right angles thereto;

Fig. 9 is a central vertical section through the construction shown Fig. 1

Fig. 10 is a vertical section through the construction shown in Fig. 5 on theplane indicated by X X; '1' 1 Fig; 1-1 is a sectional View of Fig.5 in the plane t c t 'dby' x g Y I Fig. 112 is one 'of'the'" governor "elements'fin ac? cordance with our invention;

Fig, 13 is a section. through a metal spray gun embodying a modificationoi theconstruction illustrated in Fi 5;,

Fig. 14 is a side view of one element shown in the: construction of Fig. 13;

first. element being positionedand adapte d to be operatively actedupon by the arm or. armsupon centrifugal. actuation thereof to cooperate, by 50 mechanical movement, ,with the second element to thereby restrict the compressed gas supply to the rotor of the motor;..and means'for variably adjusting the relative positionbetween the sec- 0nd element and the. initial position of the first element within a range of mechanical movement of. the firstelement defined by the angulardeflection of the armor arms between minimumjand maximum operating speeds. of the motor, The

.initial position? of the first element of the speed control meansireferred to herein, designates that position of such first element as is controlled by the deflectable arm or arms. at its or theirinitial position.

Themetal spray bodying our invention does not require any change of gearing. The same is capable of maintaim ing any numbenof practical wire feeding speeds andmay be shifted from one speed to another by a simple adjustment of thepreferably' manual control .means. Furthermore, the motor or turbine of such metal spray gu'nis' at all times 1 maintained in a stable operating condition. The

particular construction accordancewith' the preferred embodiment of our invention permits the use of these metal spray guns under sub:

gun of the gas blast type em- Fig. 15' is a graphic representation'of the prin ciple underlying the preferred embodiment of the invention;

Fig. 16 is' aview showing part of an optional construction of one element. of the invention;

Fig. 17 is a view of a central section of the showing of Fig. 1'6'on the plane indicated by XVII-XVIII, and

Fig. 18 is a diagramillustrating the principle underlying the preferred construction of the centrifugal speed responsive 'mecham'smin accord-- ance with the invention. The centrifugally actuable arm element in accordance with our preferredstructure may be any fer to obtain deflectability thereof by pivotally mounting the arm with respect to its axis of rotation'. When using one or more spring arms pivotable mounting thereof maybe dispensed with as a rule sincethese assuch will permit satisfactory deflection.

. Referring. to the drawings 1 .(Fig. 2) indicates the inlet for oxygen or other combustible supporting gas, 2, the inlet for acetylene orother combustible gas, and 3, the inlet 'for air or other gas for atomization of the metal, projection of the metal spray and driving of the turbine.- I When plug 4 of valve 5' isin the positionshown, each or the inlets registers with a corresponding hole in the plug, these holes being indicated bynumerhals 5, 6 and 1,.respectively. In this position, oxygen flows through duct ,in,to duct- II. The combustible gas flows through duct 1 2 to mix with the oxygen in duct II and the'air flows through duct I5. into chamber I6. and also flows through the side connection I! into turbine, manifold I9. As handle 0 is slightly turned from'the off position, whichis at a right angle: to the showing in Fig. 2, ducts '5, 5 and .Tin plug 4 can be so positioned that at first a relatively small amount'of combustible gas passes into duct II- and thence to the burnerv outlet to'enable'the burner to be lighted while a small amount of air passes simultaneously into manifold I9 to enable the turbine to come up to speed. Alternatively all the valve passages may be opened wide; :The rates of flow of the gases, however, must .be' then so adjusted as to establish favorable'lighting conditions which are different from the conditions as to'gas flow and air blast obtaining when the gun is in operation. The washer-'20 (Fig.- 3) defines a hole,2| of rectangular cross-section which fits closely the shank 22 (or corresponding section) (Fig. 2) of the plug 4. The washer 20 is formed with the depression 23 (Fig. -3). This washer is spring pressed, and this depression slips onto the head of pin 24when handle 8 is in the correct position for lighting the burner. This offers sufficient resistance to indicate to theoperator the lighting position. After the burner has been lighted a slight pressure againsthandle 8 forces the depression 23 out of engagement with the head of the .pin- 24. 'A further movement of handIeB causes oxygen to flow through duct I0 which establishes a melting fiamewith the ignited gas and the final movement of handle 9 to the position shown in Fig. 2 permits air to flowinto duct I5 andthence into chamber I6 and into the interior of air tip 4| under pressure to project'the sprayed metal upon the surface to be covered.

The construction of that part of the gun by will be explained by reference to Fig. 9. The wire 31 moves forward to guide 3| and through duct 32 totthe interior 33 of the burner tip 34. The mixture of air and oxygen move forward through the duct II, which is immediately behind duct 32 (the arrangement is shown in Fig, 2) and into the annular space 35. From this annular space 35 the combustible mixture} moves forward this construction and the "orificeefiect' thereby created, the adjustment of air ;tip;4| modifies the characteristics of the airblastwithoutso great a modification of the volume of ain'passing thereto the wire are engaged respectively by the-burs 52 ,45 which therod or wireis melted and projected through a number. of holes to be discharged 55 through convergent orificesj'against the wire. Thisforms a zone of g'ases undergoing combustion, whereby the ,wire'31. melts as rapidly as it is progressively advanced into the zone, for which reason this zone is referred to as a melting zone. The air from the chamber [I6 advances through the annular space 40 surrounding burner tip 34 and is projected by air nozzle'4 I in such a way as to sub-divide and propel the molten metal. The air tip 4| is threaded to' the outer shell42 of the burner so that the orifice 43defined by conical interior of air tip 4| and conical exterior of burner tip 34 may be adjusted with corresponding variations in the characteristics of the air blast. When a satisfactory adjustment has been made, the tip 4| is locked inposition by the lock nut 44. It-will be noted that the ai'rin' passing forward from the chamber I9 goes through the'constricted annular space. 45 which exerts-a definite control overthe volume of air passing. As a result of and 53. Bur 53 is carried by shaft 54, which shaft is driven by an air turbinethrough suitable intermediate: gearing which will be hereinafter described'. Shaft 54 (Fig. 4)=-also drives the gear 55 in mesh with gear 56, which in turndrives the upper bur 52.. .Bothgear 59 and-burJ52 are secured to the tubular member 5] which rotates on the spool 58 carried by pin 59 (Fig. 4);. The screw 59 is carried by the saddle 60 and. this sad.- dle is pivotally secured (Fig, 9) to frame-6 I of the gun by the hinge62. -When .cap is turned the threaded end 66,0f the screw 51 advances into the threaded member 68 which is a :part of frame GI and the spring I0 exerts pressure on thesa ddie 60, thereby forcing the upper bur 521toward the lower bur '53 and th'erebycausing the bursto engage and advance the wire 31.'.,Conversely, when cap vI55 is turned in the reverse direction, pressure of spring I0 on saddlefip is released and the burs movefreely without-engaging.and-advaricing the wire. 7 V I V The shaft 54-(Fig 4) which drives burp-.53 is mounted in ball-bearings |0;and"| I. Bearing I0 is held inframe BI and bearingI'II lisheld. in the housing I2 which is attached to frame -.6;|.;; The shaft 54 is drive n'by the worm gear 12, WhlChlIl turn is driven by the worm {14, carried by the shaft 15. Shaft '|5.-(Fig. 10 ,is arriec byban rotor drum 95.. The arrangementof the turbine blading I00 is illustrated in Fig..7an'd is'.f ,iirther' exemplified in Fig.8 showing a view of the turbine rotor drum 95 at right angles to...the showing". in Fig. 7. As evident from Fig.1 6, 'cover includes the mounting ml for the 'fballebearingfsd' and three ridges. I02 (only two1of.,.wh'ich, are illustrated) radially arranged about mounting, 'IOI tn the interior" surface of the cover." The washershaped'member I03 is madeoffine wire'mesh and rests directly upon ridges..-|,0,2.;- The-washerli i rests directly on the washe I 03. ,The' washrij I04 has the perforations. I05 .(Eig fiA IheWashers I03 and I04 are held in contact with eachlbther and with the ridges I 02by the strips I 06, which'in turn are securedtothe ridges I02 ;by thels crews I01. One resultof this construction -ijs tl'ia't the exhaust from the turbine flowslthrough perforations I05 inthe washer I 04, theneeflthro ugh the' openings in the fine screen?OiLLWhichIWasher I03 composed, and thence through-exhaust ports I III, in cover 90 (Fig. 6 and. fig'lllltherhy resulting in more quiet'operation oi-theturbihlfi; .-f 5 I which is fitted as to-be freelyslidable inrhole' 30z.

Bent clip 201 (Fig. )'-performs the ecnb eruhc' tion, first of providing adrivihgmeans through the ears 209; the buttons 202, -the spring 200- and the rotor 9-5. 'The other function is that of-absorbing by its resiliency the pounding action of weight buttons 202. When operating at high speeds, there is a natural tendency for the weight buttons 202 Which are mounted on the ends of spring arms 200 to enterinto avibratory rnotion. This motion is quickly absorbed by the resiliency of the arms of bent' clip 201. Fig. 12 is a'faee trally located in shaft 602and extends fromdts end past slot 30L Located in hole -30: is pin sot One end of pin 303 extends 'beyondfthe =endo;f shaft 602 and is-smooth and roundedofi Onthis extending end. Valve plunger "304 is s-li'dably mounted in housing 603 and is forced in thediand valve plunger.

rection toward the shaft 602 by the'action'of cdil 30 spring 305 which "acts-against pin 306 in one end of valve plunger 304.; Threadedly mounted in housing "603 is va-lve body which has threads 308 and finger wheel 3'09 and-valve seat 3111'. 'Nut 308 to prevent leakage of air'around the threads.

Air passage 3-13 is provided and-leads-fromtheair 3| holds packing material 312 against thethread W1 duct H to the space 314 between 'the valve body "301- and the housing 603. Hole-315 through the from space 314* 'to space 3H5; I fwhen valve plunger 304-is not 'in contact with valve seat 310, air-can'pass from chamber-3 l6 into -charnberfal l which surrounds" the end of "the valve plungerfi 04. Air passage 3'l8-connectsspace- 3 with the short duct'3l9. Turbine airjet 604 extends from short duct 3l'9 to the'surfaceoi housing 005 at suchan angle that air emergingyfromjet 604 impinges against turbine blades 100 to cause-turbine rotor '9'5-to-rotate. v r f In operation the supply of air-for'operatin-gthe turbine enters through "duct lfl-as previeusly de scribed." From duct 1 B'the air flows through-pas sage*3 l3 into space 3, through hole 31-5 into space 3H5; From space 3| 6 the air passes-between thevalve'seat 310 andthe'face of the valve plunger 304 into 'the *space'3l11; "Thence it goes through'the passage 318 into the short duct 3H! and emerges through'turbine'jet 604 causing turbine rotor 95 'to rotate. As turbine rotor 95 -in creases in speed, the governor weight' buttons 2-02 move out "approximately parallel to the axis of shaft 602 "in a directionaway iromithe turbine rotor '95; These buttons 202 which contact the ends 'of spring clip 20! cause fhu'b 601 to move along the shaft 602in a rdirectionaway f-ro'rn the rotor 95. As pin 300 travels alongtheshaft with thehub l, it forces pin 303-to press against the end of valve plunger 304 causing valve plunger 304 to 'approachvalveseat 3.10. Aswalve plunger 304 approaches valve seat3l0the air suppli'ed -t'o jet 604 is restricted thus 'reducing'the energy-supplied toturbine rotor '95. I Consequently atfapre determined speed the 'air flow will "be sufficiently side of the valve body301 permits passage of air speed of turbine rotor95 andithe =rotor will opere ate l at'ithis predetermined speed.- fl he operating speed of rotor' 95 is predetermined orselected either in advanceor during :operation tby' turning the thumb wheel 309 of valve -body1301.

308 causing the valve seat/310 to :getvcloserito or farther f-rom the'face of'valve plunger 3.04;; more speed is desired; the valvebodydsiturhed'in a direction to provide :more space between seat" and plunger and :whenit :is' desired toireduce the speed; it is turned: in :the-oppositfedirection thus providing less'rspa'c'eIbetweenthewalve seat :Once the speed .hasibeen pnedeterrnined adjustment I of thumb Wheel 1309, theeirotor .85 will maintain a speed which .isunearly constant.

If, for any reason, =an.increa'sesof load should the applied to themechan'is'm; zfpr dnstance #bya kink in the wir'ebeing' :fedethen: at first-:thespeed of rotor 95 1 will "beslightly reduced;

weight buttons .1202' will :meve slightly 'ztowatd rotor permittingspring 12 2! zdi'oiftoree hub 501 :along shaft 602 toward rotor 95; Thisipermitspini303 to move ba'ck and lhencdspring 305mm :mo e plunger 304 away Zfrom valve-seat 310.

permitmore air to flow -betweenlithe valve seat and the plungertandthroughthe passaige13181211111 3I9 to the jet 804, "Hence more pbweriisxsupplied to the rotor to overcome the increase in load andprevent further reductionfin speed.

Only ave'r slight reduction in speed is necessary to cause the governor to operat'eu' The fof valve 1 plunger 304- isfmadeg relatively "large and the passage =3l'6 i-n' the valve seat is made re l atively large so that a very slight lateral movement of the plunger 304 i's "sufficient to cause 'a large adjustment in-the amount "of air' which can pass between the valve seatand the plunger.

Only a very small-motion oithe governor weight 202 is required to provide a'relatively large -adj ditio'nal' amount 'of energy-"in thefiorin df air energy to act on turhine i'otorfflif If dorfa-ny reason the load on operating mechanism should suddenly become }'less, then-the turljihe rotor '95 would speedfupsli'ghtly. "Howeven even a relatively" slight increase in speed -will "be-surfi'cient to cause the governorweight' 'zflfto move against the spring clip 201-causjing=the 111113 601 and pin 300 to'move avvay frorntheroto1 95 and cause pin 303 to press against the end'of vaiv'e plunger 304' pressing; it 'closerf to' valve "seat 3110.

This action'wouldrestrict the OW' '0f air *tojet 604 and to the turbine arshes hencefpre vent further increase 'in-speed. -'Ihis construc restricted 'toprevent a further increase l of the 78 tion allows for an ample jpotentialfsupply' of energy to the rotor and also prevents H ency of the rotor to overspeedor run aw y;

. An alternative construction issh WninTtheiL- lustrations in Figs. I13 and 14." In this em'bodi ment of our invention the governor spring 2.00

and ,governor' weights-500 {are assembledlin ithe same manneras previously.descrgib edbutthey are mounted .on the reverse. side of the/rotor so that in the illustration in .Fig. .l3 theigovernor -spring 200 is mounted on the ircteres on theme to?- ward the housing -=605!. this case no sliding hub or spring :clipare; required; -$;Disc: dad-ids mounted :close :to and-parallel 5130? the"- face :of housing 605'; Atfthe center-rot ;d isc -40.0T a- ;short hub is provided which is pressed fintoithekxzenter of ball bearing 401i. "Theoutside" faneiofibeanin'g 40Lis pressed into ttheihousing $1151.30 th'atuiisc This screws the valve body230 I 'iirand out on the thread .After a very slight reduction in .speed',1however, :ithe' efgovernor 400 can rotate freely about the same axis as that of shaft 602. 'A slot 402 is provided in disc 400, as illustrated in Figs. 13 and 14. Fitted into the face of housing 605' is small pin 403. This pin limits the rotary motion of disc 400 to a motion through a small angle so that. at .each

end of this small permissible amount of motion,

the motion is' arrested by contact of .one or the other end of slot 402 against pin 403. A circular groove 404 is provided in the face of housing 605 to provide'space for flat coil spring 405. One end of coil spring 405 is bent at right angles to the plane of thespring at 405 and fits into a hole in the housing 605 at the bottom of the groove 404. The other end 401 of fiat coil spring 405 is bent at right angles in the opposite direction and fits through a hole provided for it in the disc 400. This springis sogwound as to act between the housing 605-and the disc 400 so as to tend to force it as far as it will go in a counter clockwise direction as viewed in Fig. 14. Slot 402 is cut: wide enough so that the disc 400 does not-cover the opening of air jet 504' when disc 400 has been forced by spring 405 to the limitof its travel in a counter clockwise direction*(Fig. 14). The location of pin 403 with respect to the location of the opening of jet 604' and the length of slot 402 are such that :when the disc 400 has been forced in a clockwise direction as far as it will go that part of the, disc 400 indicated at 408 will cover up the opening of the jet 604'.

Bearing 1| which is mounted on one end of shaft 602' is slidably fitted in housing 12 and housing 12' is made sufllciently long to permit of a considerable longitudinal motion of shaft 002'. At the other end of shaft 602 bearing 86 is clamped to theshaft by nut 409 and is clamped in a housing M by the threaded cap 4| I. The outside of housing M0 is provided with threads 2 which mate with threads in housing '603. On the end of bearing housing 410, a thumb wheel 3 is provided. 'If thumb wheel H3 is turned, the housing 4! 0 is screwed either in or out of the housing 603'; and as the bearing 36 is rigidly clamped in the housing 4H] and to the shaft 602 the shaft and the whole rotor assembly are forced either in or out. Hence byturning thumb wheel 3 it is possible to adjust the longitudinal position of shaft 602' and the whole rotor assembly including rotor 95, governor spring 200 and governor weight button 500. The governor weight buttons 500'are made of a sufficient length so that they can contact the face of disc 400. i

In operation air is supplied-to turbine jet 604' as previously described and emerges from the jet and acts on turbine. rotor blades I00 causing the turbine-rotor 95' to rotate." 'As the turbine rotor. 95. increases in speed the weight buttons 500 tend to move parallel to the axis of shaft 602fiin a direction towards the face of disc'400. When the weight buttons 500 contact the face of disc :400; and exert even a slight pressure against the disc, they cause friction between the disc and themselves andhence tend to rotate the disc 400.. rotate the .disc 400 is clockwise as viewed in Figure 14 and the friction of the-weight buttons 500 against'disc 400 tends to rotate it in opposition to flat coil spring 405. rotor 95' increases, thisrotary frictional force exertedby the weightbuttons 500 on'discz400 becomes suificient to overcome the force ofspring I 405 and cause the disc 400 t'o rotate through The direction in which they tend to- As the speed of' the amount of energy available for the turbine a slight angle until" part 408101 the disc-at least partially obstructs the" opening of air jet'604'. This. obstruction of the air jet by the interposition of part 408 of disc 400 between jet '604' and the turbine rotor blades I00 reduces the air energy. supplied to theturbine rotor and no further increase of speed-is possible, the .tur-

bine rotor 95' will arriveat' and maintaina pre--:

determined speed. Thisspeedis predetermined,

or may be adjusted during'op'eration by an ad;

justment of the longitudinal position of the rotor assembly which is eifectedxby screwing the thumb nut4l3 either in or out. If more speed isdesired the thumb nut 4l3jwill be turnedin such a direction as to screw the rotor assembly away from the face of disc 400-and iflessspeed required it will be turned intheopposite direction. Thefarther removed the rotor assembly slow down slightly. Assoon as it slows downeven a very small amount, the weight buttons 500 willmove away from the disc 400; if theydo not actually move.:away:-from disc 400, they will atleast reduce the pressure which they exert against the disc400thus permitting spring 405 to rotate disc 400 so as to produce less obstruction of the air. jet 604. Hence more energy is supplied to turbine rotor 95' to overcome the additional 'load which was imposed, and no further reduction of speed will occur. If, on the other hand, for any reason less load is imposed on rotor 95'; the same willspeed up slightly but even the slightest increase in speed will be sufficient to cause governor weight buttons 500 to bear more heavily against the face of disc 400., producing more friction which tends to rotate disc 400 in such, a direction as to further obstruct the opening of airJ'Ct-GMC- As thiswill reduce rotor 95 no furtherincrease in speed is possible. Although the foregoing description is complete as far as. the action-of the governor on the energy supplied to the rotor 95' is concerned, with;this embodiment-of; our invention .there is e sad i iqn ov rn g ctionw m ks's for even more sensitivity of. performance and mo're accurate speed control than is otherwise obtained.

.This. further actionis based uponsmall amounts .of-power absorbedby the governor so as to pro.-

duce moreinstantaneous action than is produced by the air, control mechanism alone. When less power is demanded-of the turbine rotor 95'. as explained above, 1 the -turbine rotor tends to. speed up slightly and hence to forcethe. governor weight buttons 500. more tightly againstthe'face of disc 7 400 causing the rotation of the disc which'reduces the air supply. In addition to this action more pressure betweenthe weight buttons l 5,00 and the face of disc 400 causes power tobe absorbed by the friction 'between'weight :buttons 500 and disc 400, This' absorption of power by friction immediately disposes of some of .the 'excess power. produced by rotor 95 and hence also helps to. revent. an increase in speed." 'Conversely, as under normal operating conditions,

' flow of air, less rrictionis produoedibetween the t weight buttons and theadiiseandhence less power is absorbed by friction which :additional :power issavailable to help overcomethe additional :load imposed upon the turbinerotor 95f. l In this embodiment. of our inventionv there-- fore, the power absorption principle has been utilized :to .its best possible; advantage inaddition :to 'the principle of control of :the :input energy to-the turbineroton: J aforementioned,the-speed governing mech I control mechanismris liilustratecl :in iconnection with :a motor of the air-turbine type, itlis "Within the scope f our invention, to 1138 our novel speed control construction 'LtO ,zgovern other types of compressed "gas motors in wire feed type :metal spray uns. v a

tfI'hepresent application :is a division of our Eco-pending application Serial. No. {421,196 filed December 1, 1941, and broadly "covers ;a centrifgally. resonsive speed governing mechanism .zhaving speed :control :means reflectingspeed control of -a rotor of a metalsprayrg'un :oIxthew-ire feed .ga's blast type by reg u-lating'sthe compressed gas supply :to "the turbine of such :metal .spraygun; our 'co-pending application Serial No, 421,194 OOVBISwfl speed governing mechanism iorisuch :rotor having speed f control means comprising speed control elements cooperating by mechanie anism in accordance witl'i our preferred con- X struction broadly comprises :a :firstvelement, cap,-

able of mechanical movement induced by 'the I operation of the armelernent, and zalseeondelement, cooperating with the first, to effect :any desired speed variably adjustable within the-entire speed range. Thus, for instance, specifieally referring .to Figs. :1 to :12, zthelfirstfelement' comprises valve' plunger A loperated' :by .the' movement ofthespring .armsa200 "by way 10f the buttons 202, clip 20], :hub; 60;l and pins 300 :and 303. The second element in thisflcase valve seat 3L0 .of valve body 30] yariab lyyadjustable within the range of mechanical movement oflthe valve plunger 304 as controlled .bytthe deflection of the spring arms 200 between zminimum and maximumspe'eds of rthe rotor 415;; Referring to Figs. 13 andltrthe first element comprisesiriction buttons Sunk-operated .Jby therle- 'flection of the spring arms 200 the second eleposestof illustration :and-nottof Elimitationand.

ment m this case-is the disc 400. ln this in-,

stance the initial position of the first element, i."e., the friction buttonsa500 is variably adjustable withrespect "to thesecond element or disc 400 by mean's of the adjustment or-the entire rotor assembly within the ranged-mechanical move- I ment of the friction buttons 500 as controlledby the deflection-of the spring arms-200 between minimumand maximum speeds-of the-rotor 9'5.

As aforementioned, the governingarm car-ry 104 attached to rotor drum I00 by screw 1'05 and bent to contact arm 10! In operation, as the centrifugal force of the weight buttonsl03 tends to move arm 10! and causeitto assume a position more nearly perpendicular to the axisof the rotation of rotor drum 100, spring "104 opposes this motion and establishes the position of weight buttons 103 for any given speedof rotor drum I00.

Our invention is not limitedto the construction of a spraygun illustrated in the foregoing examples and may be used in connectionwith any othersuitable gun construction-of the wire feed type, including those having other heating -or melting means for the wire, such as an'arc or the like and furtherincluding those' cons'tr'uctions of this type :in Which multiple wires are fed to the heating zone.

Although Within the preferred embodiments exemplified in the foregoing flgures'the; speed cal movement and actuated by centriiugally op- Eerated and :ang-ularly deflectable arms :and our co-pending application Serial No. 421,195 covers a'speed overning mechanism for such rotore'f- .iecting speed control-of suchrrotor bytfrictionel-ements cooperating by mechanical movement and actuated [by centrifugal means. a ,The .foregoingspeciiic; description is for purit is therefore :ourkintention th-at the invention be limited only by the appended claims .or their equivalent wherein we :have endeavored to claim broadly all inherent novelty.

Weclaim; v 1. .Avariable speed governing mechanism for a metal spray gun construction ot. the twire zfeed type, having-a com-pressed gas motor, compris ing first means rotatable with the rotorof said motor and *centrifugally movable with respect to their axis of rotation, against spring=-.resistance, from a predetermined initial position with respect to said-,aXia-seccnd means composedofrat least one first and one :second'element, :s'aid first elementbeing. positioned and adapted to be operatively acted upon by .said first -means upon centrifugal actuation thereof, to cooperate, .by mechanical movement and frictional contact with said second element to :thereby actuate said second elementv to restrict :thecompressed gas supply to the rotor ofsaidmotor,:andnreans :for variably adjusting the relative position between said secondelement and the initial position "of said first element within a range ,of mechanical movement of said first element defined by the centrifugal movement of :said first means between minimum and maxim-um operating speeds of said rotor.

2. A variable speed governing mechanism for a metal spray gun construction of the wire feed type, having a compressed gas moton'comprisi-ng at least one arm, rotatable with therotor of said .motori'and centrifugally deflectable for angular deflection with respect to its axis of rotation, against spring resistance, from a "predetermined initial 'positionwith respect to said axis, speed control means, composed of at least one first element positioned and adapted to be operatively acted upon by said arm upon centrifugal cac- 3. A variable speed governing mechanism in accordance with claim 2, in which said first and second elements cooperate by mechanical movement and frictional contact to thereby restrict the gas supply to said rotor.

4. A variable speed governing mechanism for a metal spray gun construction of the wire feed type, having a compressed gas motor, comprising at least one arm, rotatable with the rotor of said motor and centrifugally deflectable for angular deflection with respect to its axis of rotation, against spring resistance, from a predetermined initial position with respect to said axis, speed control means, composed of at least one first element, rotatable with said arm, and positioned andadapted to be operatively acted upon by said arm upon centrifugal actuation thereof, so as to limitedly move, against the force of a spring, to thereby restrict the gas supply to said rotor between said rotor and the compressed gas jets therefor and means for variably adjusting the relative position of said first element with respect to the initial position of said second element.

5. A variable speed governing mechanism in accordance with claim 4 in which said arm is centriiugally deflectable from a predetermined initial position of at least 60 with respect to said axis.

6. A variable speed governing mechanism in accordance with claim 4 in which said arm is centrifugally deflectable from a predetermined initial position of from 70 to 80 with respect to said axis.

7. In a variable speed governing mechanism for a metal spray gun construction of the wire feed type having a compressed gas motor, the improvement in speed control means by power input control comprising a disc element limitedly rotatable against spring force and carrying an obstruction normally substantially out of registry with the compressed gas jet for the rotor of said motor, a friction element, rotatable with said rotor, positioned and adapted to be operatively acted upon by centrifugal speed responsive means to move said obstruction by frictional engagement with said disc element from limitedly to completely into said registry, and means for variably adjusting the relative position between said disc element and initial position of said friction element within a range of mechanical movement of said friction element defined by minimum and maximum operating speeds of said rotor.

8. In a variable speed governing mechanism for a metal spray gun construction of the wire feed type having a compressed gas motor, the improvement in speed control means by power input control comprising an axially slidable rotor assembly for said motor, having at least two substantially coaxially aligned symmetrically arranged, radial spring arms, carrying weights adjacent the free ends thereof, said arms being mounted on said rotor and centrifugally deflectable for angular deflection with respect to their axis of rotation, against spring resistance, from a. predetermined initial position of from to with respect to said axis, a disc, and rotatably mounted substantially coaxial with said axis, a cut-out in said disc, a spring normally holding said cut-out in substantial registry with the compressed gas jet for said rotor against rotation in the direction of said arms, and screw means for variably adjusting the position of said rotor assembly with respect to said disc.

ARTHUR P. SHEPARD. HERBERT S. INGHAM. 

